In the first paper of our new Know Your Tools series, Sebastien Tricaud from the French Honeynet Project Chapter and Victor Amaducci from the University of Campinas, focus on Picviz. After a brief overview on parallel coordinates, Picviz architecture, and installation procedure, three real-world examples are presented that illustrate how to identify attacks from large amounts of data: Picviz is used to analyze SSH logs, Apache access logs and network traffic. With these examples, it is demonstrated how Picviz can find attacks that previously have been hidden.